The purpose of this project is to characterize the extents and time scales of structural reorganization associated with redox state changes in biological redox proteins in disordered media, such as liquids, oriented membrane multilayers and frozen glasses, using x-ray scattering in the small to mid-angle domain (0.005 [unreadable]-1<q<2 [unreadable]-1). Protein dynamics and nuclear reorganization energies are controlling features of biological electron transfer, although the amplitudes and time scales of these motions have not been well characterized. The goal of this project is to correlate structural reorganization, detected by solution x-ray scattering, directly with biological electron transfer activity in three redox protein systems: cytochrome c, rutheniated cytochrome c, and the bacterial photosynthetic reaction center. Initially, proof-of-principle experiments will be carried out using chemically generated, stable oxidized and reduced redox states of proteins.